Piston adder apparatus



H. A. PANISSIDI PISTON ADDER APPARATUS Aug. 16, 1966 Filed NOV. 13, 1964 2 Sheets-Sheet 1 QOZmjOm INVENTOR. Hg) A. PANISSIDI BY M ATTORNEY United States Patent 3,266,377 PISTON ADDER APPARATUS Hugo A. Panissidi, Peekskill, N.Y., assignor to International Business Machines Corporation, Armonk, N.Y., a corporation of New York Filed Nov. 13, 1964, Ser. No. 411,066 14 Claims. (Cl. 91-167) a separate cylinder which includes two hose connections on either side of the piston such that a relative pressure increase applied through one or the other hose will move the piston to one or the other end of the cylinder.

The piston rod of the first piston in the series is mounted to a stationary reference, and each succeeding piston rod is mounted to the preceding piston cylinder. Each of the piston cylinders is generally of greater length than the preceding piston cylinder. Consider a series of five piston cylinders having lengths of one, two, four, eight, and sixteen units respectively. Thus, with only the first piston actuated the overall apparatus moves one unit. With only the second piston actuated the overall apparatus moves two units, with the first and second pistons actuated the overall apparatus moves three units. It can be seen that by actuating the proper combinations of pistons that the overall apparatus can be made to extend any unit distance from one unit to thirty-one units from the stationary reference. The overall apparatus would consist of five chambers with five pistons. Each chamber would have two hoses for a total of ten hoses. If greater or less distances are required, cylinders may be added or removed according to the situation, however, each cylinder would contain one piston and require two hoses.

An improved piston adder apparatus has been devised which performs the same function as the above-described device, but wherein by unique design much of the mass and complexity of the conventional piston adder apparatus is avoided.

An object of the present invention is to provide a high speed, low mass piston adder apparatus.

Another object of the present invention is to provide an improved piston adder apparatus.

Still another object of the present invention'is to provide a multi-cylindered piston adder apparatus having rigid support between cylinders.

Another object of the present invention is to provide a piston adder apparatus wherein the piston rods serve as fluid lines.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings.

In the drawings:

FIG. 1A and 1B combined together show a schematic section of a piston adder apparatus following the prin fluid and are connected via tube 32. Piston 14 is connected to a stationary reference 34 via piston rod 36. Piston 14 is connected to hollow piston rod 36 by pin 15. Piston rod 36 is hollow and is joined to a source of constant fluid pressure (pressure compensated pump 37) via connector tube 38. The pressure applied by pressure compensated pump 37 into piston rod 36 via connector tube 38 is maintained constant. Piston 16 is connected by pin 17 to a hollow fluid filled piston rod 40' which extends into chamber 26 of cylinder 12 and is connected to piston 22 by pin 23. Piston 24 is connected by pin 25 to a hollow, fluid filled piston rod 42 which extends out of chamber 28 and may terminate in suitable load 44. Piston rod 36 and piston 14 include an opening 39 providing a path from the inside of piston rod 36 to the inside of chamber 18. Likewise, piston rod 40 and piston 16 include a similar opening 41, piston rod 40 and piston 22 include an opening 43 and piston rod 42 and piston 24 include an opening 45. Thus, a fluid path exists from pump 37 through tube 38, through piston rod 36, through opening 39 into chamber 18, through tube 30 into chamber 20, through opening 41, through piston rod 40 through opening 43 into chamber 26, through tube 32 into chamber 28, and through opening 45 into piston rod 42. Pump 37 maintains the pressure within this fluid path at a constant value.

Each of the chambers 18, 20, 26, and 28 has a hose 4'6, 48, 50, and 52 respectively connected thereto. Each of the hoses is connected to its respective one of chambers 18, 20, 26, and 28 on the side of each of the associated pistons 14, 16, 22, and 24 which is opposite to the sideto which the piston rods are connected. The hoses 46, 48, 50, and 52 are respectively connected to a separate three way valve 54, 56, 58, and 60. When valves 54, 56, 58, and 60 are in one position the associated. hoses 46, 48, 50, and 52 are connected to pump 37. When valves 54, 56, 58, and 60 are in their other position the associated hoses 46, 48, 50, and 52 are con-' nected to reservoir 51. When valves 54, 56, 58, or 60 are in their reservoir position no pressure is applied through associated hoses 46, 48, 50, or 52, however, when valves 54, 56, 58, or 60 are in their pump position, a fluid under pressure P is applied through associated hoses 46, 48, 50, or 52. Cylinder 10' includes a separator 62 separating chambers 18 and 20 and cylinder 12 includes a separator 64 separating chambers 22 and 24. Separators 62 and 64 respectively include hollow rods 66, 68, 70, and 72 which protrude from each side thereof. Hollow rods 66, 68, 70, and 72 each respectively contain an orifice 74, 76, 78, and 80. Piston 14 contains a cavity 82 into which rod 66 fits when piston 14 is in its unextended position. Likewise, piston 16 contains a cavity 84 into which fits rod 68, piston 22 contains a cavity 86 into which fits rod 70, and piston 24 contains a cavity 88 into which fits rod 72 when pistons 16, 22, and 24 are in their unextended position. The unextended positions of pistons 14, 16, 22, and 24 are when they are proximate to separators 62 and 64. End caps 90 and 92 of cylinder 10 and end caps 94 and 96 of cylinder 12 also contain cavities into which fit snubber diameters 98, 100, 102, and 104 which protrude from the piston rod sides of pistons 14, 16, 22, and 24 respectively, when pistons 14, 16, 22 and 24 are in their extended positions.

When piston 14 is moved from its unextended position shown in the drawing to its extended position (to be later described), snubber diameter 98 will enter the cavity in end cap 90 and the fluid trapped therein will bleed through orifice 108 in piston rod 36. Thus, a damping effect occurs reducing the impact of the stroke. When piston 14 is returned to the unextended position on the return stroke, hollow rod 66 enters into cavity 82 and the fluid trapped therein bleeds through orifice 74 also causing damping and reducing impact. The same is true of piston 16 and bleeder orifices 76 and 108, piston 22 and bleeder orifices 78 and 118, and piston 24 and hleeder orifices 88 and 112.

The piston rods 36, 40, and 42 have cross-sectional areas equal to one-half the cross-sectional area of the piston to which they are connected, thus with constant fluid pressure in the piston rods, only one-half the amount of such pressure need be applied to the other side of the pistons to equalize the force.

Actually, valves 54, 56, 58, and 60 being connected to pump pressure when they are in their pressure position, when any valve is in its pressure position, fluid under pressure P is applied to the side of the associated piston opposite to the piston rod. Since the force on the piston rod side of the piston is P-A and the force on the other side of the piston is equal to P-ZA, the associated piston will move toword its extended position. When the valve is moved back to its reservoir position the pressure falls to Zero and the force equal to PA applied through the piston rod returns the piston to its unextended position.

In the drawing the piston adder is in its completely retracted position, and the load 44 is at its initial position. In such case valves 54, 56, 58 and 60 are in their reservoir position. When valve 54 is actuated to its pressure position pump fluid under pressure P is applied from valve 54 via hose 46 and the resulting force which is equal to P-2A will be greater than the P-A force applied by piston rod 36, causing cylinder 10 to move to the right until snubber diameter 98 is in the orifice in end cap 90. The distance that cylinder 10 moves in such instance is designed to be one unit. Thus, cylinder 12 and load 44 being mechanically connected to cylinder 10 also move one unit to the right. When chamber 18 moves to the right with respect to piston 14, the pressure in the piston rod side of chamber 18 increases and the fluid therein is forced through opening 39 in rod 36 and is conveyed through tube 38 through valve 54 and through hose 46 into the right side of chamber 18, thereby occupying a portion of the resultant increased volume due to the movement of chamber 18 to the right. The additional displaced volume is made up by the pump. The pressure in piston rod 36 and the pressure through hose 46 is thus maintained at P. When valve 54 is reset to its reservoir position the pressure applied through hose 46 falls to zero and the force which is equal to P-A in piston rod 36 causes chamber 18 to move to the left with respect to piston 14, thereby returning cylinder 10, cylinder 12, and load 44 to their initial positions.

The same operation is true for each of the other chambers and pistons when their associated valves are actuated except that each of the succeeding chambers are greater in length. Thus, when valve 56 is moved to its pressure position the pressure in hose 48 is raised to P and piston 16 is extended two units of lengths with respect to chamber 28 and cylinder 12 and the load 44 consequently move two units of distance. When piston 16 moves, the fluid in the right side of chamber 2 is forced back through tube 30 into the left side of chamber 18, through opening 39, into piston rod 36 and finally through tube 38 back through valve 56.

Chamber 26 is four units in length so that when valve 58 is moved to its pressure position the pressure in hose 50 is increased to P and chamber 26 (and consequently load 44) is ultimately moved four distance units to the right and chamber 28 is eight units in length so that when valve 60 is moved to its pressure position the pressure in hose 52 is increased to P and ultimately the load 44 is moved eight distance units to the right.

The valves 54 through 66 may be actuated in combinations so that the pressures in some or all the hoses 46, 48, 58, 52 are increased at the same time. By selecting the combinations, the load 44 can be moved from one to fifteen units of length. The combinations and re- .sultant distances are set forth as follows:

Actuated valve: Distance load is moved 54 One unit.

56 Two units. 54, 56 Three units. 58 Four units. 54, 58 Five units. 56,58 Six units.

54, 56, 58 Seven units. 60 Eight units. 54, 60 Nine units. 56, 60 Ten units.

54, 56, 60 Eleven units. 58, 60 Twelve units. 54, 58, 60 Thirteen units. 56, 58, 60 Fourteen units. 54, 56, 58, 60 Fifteen units.

When more than one of the valves 54, 56, 58, or 60 is actuated to its pressure position a greater amount of fluid will be displaced in the associated chambers, however this fluid will be fed back through the fluid path into tube 38 and be returned via the actuated valves. If the volume of fluid displaced when piston 14 moves with respect to chamber 18 is V, then the volume displaced when piston 16 is moved with respect to chamber 20 is 2V, the volume displaced from chamber 26 is 4V and the volume displaced from chamber 28 is 8V. For example, if valves 54 and 58 were actuated to their pressure positions load 44 would move five distance units and a volume of fluid V from chamber 18 plus a volume 4V from chamber 26 would be transferred into tube 38. However, the volume of the right side of chamber 18 is now increased by a volume greater than V and the volume of the right side of chamber 26 is now increased by a volume greater than 4V so that the 5V volume of fluid fed through tube 38 is returned through valves 54 and 58 to chambers 18 and 26 in a V and 4V division with additional fluid being supplied by the pump 37.

The valves 54, 56, 58, and 60 may be actuated by means of solenoid or relays, etc. such as solenoids 53, 55, 57, and 59 connected to a source of binary input signals (not shown). Valve 54 would be responsive to binary signals representative of the value 2, valve 56 responsive to the 2 signal value, valve 58 responsive to the 2 signal value, and valve 60 responsive to the 2 signal value.

It is obvious that if another cylinder were included in the piston adder having chambers with lengths of sixteen and thirty-two units, the load 44 could be moved up to sixty-three units of length. Thus, the piston adder 'of the present invention is not limited to any particular number of stages. It is also obvious that the lengths specified in the present embodiment may be changed depending on the application of the piston adder. End caps 74, '76, 78, and are shown mounted on cylinders 10 and 12 by threaded connections sealed with thread sealant so that fine adjustments in length may be made.

It is to be noted that the piston adder of the present invention uses only half the flexible pressure hoses as required by conventional piston adders. Since the pres sure hoses must move with the adder a significant saving in weight, drag and inertia is realized. By having the piston rods also serve as hydraulic lines and by arranging the pistons back-to-back in a single cylinder a saving in material, weight and unnecessary length is effected. Further, since the pin connections between pistons and piston rods are inside the cylinders, a more rigid cylinder to cylinder connection results, therefore requiring no external guides or supports. These advantages become more significant as more stages are included in the piston adder.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art .5 that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. A piston apparatus comprising at least one piston cylinder,

said piston cylinder including first and second fluid filled chambers separated by a center member;

a first piston movably mounted in said first chamber and a second piston movably mounted in said second chamber;

a first piston rod connected through the end of said first chamber to said first piston, said first piston rod being a fluid filled tube, said first piston rod having an orifice therein providing a fluid path to said first chamber;

a second piston rod connected through the end of said second chamber to said second piston, said second piston rod being a fluid filled tube, said second piston rod having an orifice therein providing a fluid path to said second chamber;

a fluid filled connecting tube connecting said first and second fluid fille-d chambers;

and means connected to said piston cylinder for selectively moving said first piston and said second piston.

2. A piston apparatus comprising a plurality of separate piston cylinders,

each of said piston cylinders including first and second fluid filled chambers separated by a center member;

a first piston in said first chamber and a second piston in said second chamber of each of said piston cylinders;

a separate first piston rod connected through the end on said firs-t chamber to each of said first pistons, said first piston rods being fiuid filled hollow tubes;

3. separate second piston rod connected through the end of said second chamber to each of said second pistons, said second piston rods being fluid filled tubes;

the second piston rod of each said piston cylinders and the first piston rod of the successive one of said piston cylinders being a common fluid filled rod, said plurality of piston cylinders thereby forming a serially connected array of cylinders;

a fluid filledconnecting tube connecting said first and second fluid filled chambers of each of said piston cylinders;

and means connected to each of said piston cylinders for selectively moving said first piston and said second piston in each of said piston cylinders.

3. A piston apparatus according to claim 2 wherein said first piston rod of said first piston cylinder in said series is maintained stationary, and wherein the movement of each piston from said first position proximate said associated center member to said second position at the end of said associated chamber produces an equal movement of said successive ones of said piston cylinders in said series.

4. A piston apparatus according to claim 3 wherein the movement of said second piston rod of the last piston cylinder in said series array is the cumulative addition of the movements of each of the pistons in each of the piston cylinders in said series array.

'5. A piston apparatus according to claim 4 wherein the length of each of said second chambers of each of said piston cylinders is twice as long as the length of said first chamber therein, and wherein the length of each of said first chambers in each of said piston cylinders is twice as long as the length of the second chamber of the preceding piston cylinder in said series array.

6. A piston adder apparatus comprising at least one piston cylinder,

said piston cylinder including first and second fluid filled chambers separated by a center member;

a first piston movably mounted in said first chamber and a second piston movably mounted in said second chamber;

a first piston rod connected through the end of said first chamber to said first piston, said first piston rod being a fluid filled tube, said first piston rod having an orifice therein providing a fluid path to said first chamber;

a second piston rod connected through the end of said second chamber to said second piston, said second piston rod being a fluid filled tube, said second piston rod having an orifice therein providing a fluid path to said second chamber;

a fiuid filled connecting tube connecting said first and second fluid filled chambers;

a fluid pump connected to said first piston rod for maintaining said fluid in said first piston rod, said first chamber, said connecting tube, said second chamber, and said second piston rod at a given constant pressure;

a first hose connected between said first chamber and said pump;

a second hose connected between said second chamber and said pump;

a first valve connected to said first hose for selectively controlling the pressure from said pump through said first hose to said first chamber between said given constant pump pressure and zero pressure such that when said given constant pressure from said pump is applied to said first chamber said first piston moves from a first position proximate said center member to a second position proximate to the end of said first chamber opposite said center member, and when Zero pressure is applied to said first chamber and said first piston is in said second position, said first piston will return to said first position proximate said center member;

and a second valve connected to said second hose for selectively controlling the pressure from said pump through said second hose to said second chamber between said given constant pump pressure and zero pressure such that when said given constant pressure from said pump is applied to said second chamber, said second piston moves from a first position proximate said center member to a second position proxi mate to the end of said second chamber opposite said center member, and when zero pressure is applied to said second chamber and said second piston is in said second position, said second piston will return to said first position proximate said center member.

7. A piston adder apparatus according to claim 6 wherein the length of said second chamber is twice the length of said first chamber.

8. A piston adder apparatus comprising a plurality of separate piston cylinders,

each of said piston cylinders including first and second fluid filled chambers separated by a center member;

a first piston movably mounted in said first chamber and a second piston movably mounted in said second chamber of each of said piston cylinders;

a separate first piston rod connected through the end on said first chamber to each of said first pistons, said first piston rods being fluid filled hollow tubes;

a separate second piston rod connected through the end of said second chamber to each of said second pistons, said second piston rods being fluid filled tubes;

the second piston rod of each said piston cylinders and the first piston rod of each successive one of said piston cylinders being a common fluid filled rod, said plurality of piston cylinders thereby forming a serial- 1y connected array of cylinders;

a fluid filled connecting tube connecting said first and second fluid filled chambers of each of said piston cylinders;

a fluid pump connected to said first piston rod of the first piston cylinder in said series 'array for maintaining said fluid in said first piston rod, said first chamber, said connecting tube, said second chamber, and said second piston rod of each of said piston cylinders at a given constant pressure;

a separate first hose connected between said first chamber of each of said piston cylinders and said pump;

a separate second hose connected between said second chamber of each of said piston cylinders and said P p;

a separate first valve connected to each of said first hoses for selectively controlling the pressure from said pump through each of said first hoses to each of said first chambers between said given constant pump pressure and Zero pressure such that when said given constant pressure from said pump is applied to each of said first chambers, each of said first pistons therein moves from a first position proximate said center member to a second position proximate to the end of said first chamber opposite said center member, and when zero pressure is applied to each of said first chambers and said first piston there is in said second position, said first piston will return to said first position proximate said center member;

and a separate second valve connected to each of said second hoses for selectively controlling the pressure from said pump through each of said second hoses to each of said second chambers between said given constant pump pressure and zero pressure such that when said given constant pressure from said pump is applied to each of said second chambers, each of said second pistons moves from a first position proximate said center member to a second position proximate to the end of said second chamber opposite said center member, and when zero pressure is applied to each of said second chambers and said second piston therein is in said second position, said second piston will return to said first position proximate said center member.

9. A piston adder apparatus according to claim 8 wherein said first piston rod of said first piston cylinder in said series is maintained stationary, and wherein the movement of each piston from said first position proximate said associated center member to said second position at the end of said associated chamber produces an equal movement of said successive ones of said piston cylinders in said series.

10. A piston adder apparatus according to claim 9 wherein the movement of said second piston rod of the last piston cylinder in said series array is the cumulative addition of the movements of each of the pistons in each of the piston cylinders in said series array.

11. A piston adder apparatus according to claim 10 wherein the length of each of said second chambers of each of said piston cylinders is twice as long as the length of said first chamber therein, and wherein the length of each of said first chambers in each of said piston cylinders is twice as long as the length of the second chamber of the preceding piston cylinder in said series array.

12. A piston adder apparatus according to claim 11 further including a load connected to the second piston rod of the last piston cylinder in said series array;

and wherein said first and second valves connected to said first and second hoses are selectively actuated to selectively apply said given constant pump pressure to selected ones of said first and second piston chambers for moving the associated ones of said first and second pistons from their first position to their second position, thereby moving said load a distance equal to the cumulative value of the lengths of said selected ones of said first and second piston chambers.

13. A piston apparatus comprising a plurality of piston cylinders each having first and second chambers linearly disposed and separated by a center member;

first and second piston-s respectively movably mounted in said first and second chambers and adapted to move in opposite directions away from said center wall to the respective end of each first and second chamber,

each of said second pistons of said piston cylinders connected to the first piston of another of said piston cylinders by common piston rods to form a serial 'array of said piston cylinders;

a second piston rod connecting said second piston of the last piston cylinder in said serial array to a load means;

said first piston rod, said second piston rod, and said common piston rods containing fluid and said first and second chambers in each of said piston cylinders containing fluid;

means for applying pressure to said fluid in said first, second and common piston rods and to said fluid in each of said first and second chambers,

and means connected to each of said piston cylinders for selectively moving said first and second pistons in each of said piston cylinders.

14. A piston apparatus according to claim 13 wherein said means for applying pressure includes valve means for controlling said pressure applied to said first and second chambers in each of said piston cylinders for selectively moving each of said first and second pistons therein.

References Cited by the Examiner UNITED STATES PATENTS 691,692 1/ 1902 Von Zweigbergk 91- 167 2,010,158 8/1935 Kleinschmidt 91167 2,886,005 5/1959 Bryan 92-111 3,162,365 12/1964 Gizeski 9l167 FOREIGN PATENTS 960,399 6/ 1964 Great Britain.

MARTIN P. SCHWARDON, Primary Examiner.

SAMUEL LEVINE, Examiner.

P. T. COBRIN, Assistant Examiner. 

1. A PISTON APPARATUS COMPRISING AT LEAST ONE PISTON CYLINDER, SAID PISTON CYLINDER INCLUDING FIRST AND SECOND FLUID FILLED CHAMBERS SEPARATED BY A CENTER MEMBER; A FIRST PISTON MOVABLY MOUNTED IN SAID FIRST CHAMBER AND A SECOND PISTON MOVABLY MOUNTED IN SAID SECOND CHAMBER; A FIRST PISTON ROD CONNECTED THROUGH THE END OF SAID FIRST CHAMBER TO SAID FIRST PISTON, SAID FIRST PISTON ROD BEING A FLUID FILLED TUBE, SAID FIRST PISTON ROD HAVING AN ORIFICE THEREIN PROVIDING A FLUID PATH TO SAID FIRST CHAMBER; A SECOND PISTON ROD CONNECTED THROUGH THE END OF SAID SECOND CHAMBER TO SAID SECOND PISTON, SAID SECOND 